Does anyone here experienced overheating on their S10? It happened to me twice already during normal use. It is so hot that i have to place it somewhere. I donk know if this is an isolated case or there are other people experiencing the same. I just bought it last month.
It could be that you have background apps running that are using up your phone's resources. Does the issue persist if you close all your recently used apps and restart the phone?
You can also experiment with battery optimization features (e.g. Battery Saver mode) to see if that helps with the heat. Like @Echo1 suggested as well, leaving the phone in direct sunlight can contribute to overheating.
Streaming video can be resource-intensive, but it shouldn't cause your phone to overheat...
Just out of curiosity, is the weather hot where you are? If so, sometimes having a fan blowing cool air onto your phone can be a quick remedy! Also, removing your case (if you have one) will help the heat dissipate quicker as well.
